package com.kuang.lesson01;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;

public class GamePanel extends JPanel implements KeyListener,ActionListener{

    int length;
    int[] snakeX = new int[600];
    int[] snakeY = new int[500];
    String fx;

    boolean isStart = false;
    boolean isFall = false;

    Timer timer = new Timer(100,this);

    int foodx;
    int foody;

    int score;

    Random random = new Random();

    public GamePanel() {
       init();
       this.setFocusable(true);
       this.addKeyListener(this);
       timer.start();
    }

    public void init(){
        length = 3;
        snakeX[0] = 100;
        snakeY[0] = 100;
        snakeX[1] = 75;
        snakeY[1] = 100;
        snakeX[2] = 50;
        snakeY[2] = 100;
        fx = "R";

        foodx = 25+25*random.nextInt(34);
        foody = 75+25*random.nextInt(24);

            score = 0;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);//清屏
        this.setBackground(Color.WHITE);
        Data.header.paintIcon(this,g,25,11);
        g.fillRect(25,75,850,600);

        g.setColor(Color.WHITE);
        g.setFont(new Font("微软雅黑",Font.BOLD,18));
        g.drawString("长度"+length,750,35);
        g.drawString("分数"+score,750,50);

        Data.food.paintIcon(this,g,foodx,foody);

        if(fx.equals("R")){
            Data.right.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("L")){
            Data.left.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("U")){
            Data.up.paintIcon(this,g,snakeX[0],snakeY[0]);
        }else if (fx.equals("D")){
            Data.down.paintIcon(this,g,snakeX[0],snakeY[0]);
        }
        for (int i = 1; i< length;i++) {
            Data.body.paintIcon(this, g, snakeX[i], snakeY[i]);
        }



        if(isStart==false){
            g.setColor(Color.WHITE);
            g.setFont(new Font("微软雅黑",Font.BOLD,40));
            g.drawString("按下空格开始游戏",300,300);
        }

        if (isFall){
            g.setColor(Color.RED);
            g.setFont(new Font("微软雅黑",Font.BOLD,40));
            g.drawString("游戏失败，按下空格重新开始",300,300);
        }
    }


    @Override
    public void keyTyped(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();

        if(keyCode == KeyEvent.VK_SPACE){
            if(isFall){
                isFall = false;
                init();
            }else{
                isStart = !isStart;
            }

            repaint();
        }

        if(keyCode == KeyEvent.VK_UP){
            fx = "U";
        }else if(keyCode == KeyEvent.VK_DOWN){
            fx = "D";
        }else if(keyCode == KeyEvent.VK_LEFT){
            fx = "L";
        }else if(keyCode == KeyEvent.VK_RIGHT){
            fx = "R";
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if(isStart && isFall == false){

            if (snakeX[0] == foodx && snakeY[0] == foody){

                length++;
                score =score + 10;
                foodx = 25+25*random.nextInt(34);
                foody = 75+25*random.nextInt(24);
            }
            for(int i =length-1;i>0;i--){
                snakeX[i] = snakeX[i-1];
                snakeY[i] = snakeY[i-1];
            }
            if(fx.equals("R")){
                snakeX[0] = snakeX[0]+25;
                if(snakeX[0]>850){ snakeX[0] = 25; }
            }else if(fx.equals("L")){
                snakeX[0] = snakeX[0]-25;
                if(snakeX[0]<25){ snakeX[0] = 850; }
            }else if(fx.equals("U")){
                snakeY[0] = snakeY[0]-25;
                if(snakeY[0]<75){ snakeY[0] = 650; }
            }else if(fx.equals("D")){
            snakeY[0] = snakeY[0]+25;
                if(snakeY[0]>650){ snakeY[0] = 75; }
        }

        for (int i = 1;i < length ;i++){
                if(snakeX[0] == snakeX[i] && snakeY[0] == snakeY[i]){
                    isFall = true;
                }
            }

            repaint();
        }
        timer.start();
    }
}
